Mixing four-dimensional equipped and unequipped aircraft in the terminal area

The prublesn Of mixin ~ four-dimensional (4-1)) equipped aircraft (aircraft equipped with on board guidance 'lst,'ms Ihat tan predict and control the touchdown lime of an aircraft to au accuracv of a few seconds Ihroul:h,lUI the descent) with uncquipp,'d aircraft In till ' terminal area bas been In~eslil:llte'd vla a real-time air traffic control simulation studS. The objeethe of thb study was to develop scheduling algorithms and operatinnal procedures for various traffic mixes that ranged from 15 to 75~' ~ 4-1) equipped aircraft. Results indicate substantial redudion in controller workload and an increase in orderliness when more limn 25 % of the atrcrart arc 4-1} equipped. Moreover, this is an·ompll.shed without increl1sing the workload or adding delays for the unequipped aireral'!.